In institutional environments such as prisons where food containers, or trays, are transported, distributed or collected, the containers are typically stacked on carts and wheeled to various distribution and collection locations. However, containers stacked above a certain height, particularly if low in weight, tend to topple as the cart is moved. As a result, carts are often provided with sidewalls and doors or the like which keep the containers properly stacked. However, such sidewalls and doors limit access, increase weight, require high maintenance and add to the cost of such carts when compared to open carts. In addition, with a cart having walls, visibility is limited and security issues are raised by the increased possibility of hiding something in the cart.
Another way to maintain stack stability is to provide a restraining strap, or belt, which holds the stack of containers together during the transporting from the kitchen preparation area to the serving area. At the same time, it has been found that tightly stacked thermally-insulated food containers are more likely to keep the food at proper serving temperatures, which is a feature particularly important when the length of time from preparation and loading to delivery is substantial.
However, while such a restraining strap works well to tightly stack a single stack of food containers, the strapping mechanism is unable to properly seal more than one stack at a time. For example, when containers are stacked in two or more side-by-side stacks, a single strap tensions the outside walls of the stacks downwardly while drawing the containers together in the horizontal direction, which forces the inside walls upwardly into a peak. Although the containers may still be transported, such a peaked arrangement inhibits proper container sealing. The irregular stack heights found in typical food containers along with warping of the containers from normal use and wear tends to amplify the problem. For example, individual containers are supposed to be two-and-one-half inches high, but typically vary by approximately one-sixteenth of an inch. When randomly stacked, for example into a stack of sixteen containers, these tolerances combine such that side-by-side stacks often have height differentials of one-half inch, with even greater differentials possible.
Thus, strapping mechanisms are limited to tensioning a single stack of food containers if proper sealing is desired. However, based on the shape of typical containers, the need for a certain width of the cart to provide stability, and on the dimensions of the doorways that the carts must traverse, the cart dimensions lend themselves to having double stacks of containers arranged in substantially parallel, side-by-side rows, several sets long.
When food carts are employed in a secure institution such as a prison or jail, the distances from a central preparation location to an inmate dining area may be substantial, making proper sealing for temperature retention important if the food is intended to be served hot or chilled. For example, typical local health boards require hot food to be served above 140 degrees Fahrenheit and chilled food to be served below 45 degrees Fahrenheit. Some institutions attempt to solve this problem of temperature retention by shipping the food in bulk to a location near the ultimate destination, where it is then portioned and distributed. However, this is not as desirable as having individual food containers since bulk distribution requires having multiple sanitized food preparation areas, necessitating extra personnel to portion the food and clean the area. Moreover, individual food containers are preferred over group serving arrangements since this system ensures that everyone receives an appropriate serving, a situation which will not necessarily occur with bulk distribution unless the food is very carefully distributed by prison personnel.
At the same time, the prison or jail environment generates product specifications that are both unique and extremely demanding. For example, institutional food delivery carts are subject to substantial abuses including frequently repeated intentional attempts at destruction. The carts must therefore be extremely durable and robust to withstand the physically harsh environment for any length of time. In addition, the delivery carts must be constructed in a manner that prevents their being easily dismantled into their component parts which may be used as weapons.